1.4 Combination of GEM, VPA and GCV in NPC treatment In EBV-related malignancy, antiviral drugs exhibit no direct effect on cancer cell except when used combined with epigenetically active agents (17, 18). Recently, Wildeman et al, had shown some efficacy by combining chemotherapy of GEM with VPA and GCV in control of locally advanced/metastatic NPC patients (13). In this article, both GEM and VPA could shift EBV from latent phase into lytic phase and had synergetic effect when combined used. Further adding GCV in this regimen could suppress virion formation. The combination therapy had been tested in three locally advanced/metastatic NPC patients showing promising results with tumor regressing/stable in image and plasma EBV DNA load monitoring with few side effects Similar manageable side effects of these three drugs combined treatment were also proved by Stoker et al (19). These results encouraged us to develop a more practical regimen in this trial.